This invention relates generally to the provision or supply of inflation gas and, more particularly, to an assembly for providing or supplying an inflation gas such as may be desired for certain inflatable passive restraint systems for use in vehicles for restraining the movement of an occupant in the event of a vehicular collision.
It is well known to protect a vehicle occupant by means of safety restraint systems which self-actuate from an undeployed to a deployed state without the need for intervention by the operator, i.e., “passive restraint systems.” Such systems commonly contain or include an inflatable vehicle occupant restraint or element, such as in the form of a cushion or bag, commonly referred to as an “airbag cushion.” In practice, such airbag cushions are typically designed to inflate or expand with gas when the vehicle encounters a sudden deceleration, such as in the event of a collision. Such airbag cushions may desirably deploy into one or more locations within the vehicle between the occupant and certain parts of the vehicle interior, such as the doors, steering wheel, instrument panel or the like, to prevent or avoid the occupant from forcibly striking such parts of the vehicle interior. For example, typical or customary vehicular airbag cushion installation locations have been included in the steering wheel, in the dashboard on the passenger side of a car, along the roof line of a vehicle such as above a vehicle door, and in the vehicle seat such as in the case of a seat-mounted airbag cushion. Other airbag cushions such as in the form of knee bolsters and overhead airbags also operate to protect other or particular various parts of the body from collision.
In addition to an airbag cushion, inflatable passive restraint system installations also typically include a gas generator, also commonly referred to as an “inflator.” Upon actuation, such an inflator device desirably serves to provide an inflation fluid, typically in the form of a gas, used to inflate an associated airbag cushion.
Various types or forms of inflator assemblies or devices have been disclosed in the art for use in inflating an airbag cushion such as used in inflatable restraint systems. One type of known inflator device derives inflation gas from a combustible pyrotechnic gas generating material which, upon ignition, generates a quantity of gas sufficient to inflate the airbag.
Gas generating materials used in such inflator assemblies desirably produce or provide sufficient gas mass flow in a desired time interval to achieve the required work impulse. In practice, the temperature of the gas can and does influence the amount of work the generant gases can do. Excessively high gas temperatures are generally sought to be avoided due to possible associated complications such as burns and/or other forms of thermal damage. In addition, applications with high gas temperatures can lead to an excessive reliance and/or sensitivity of the gas to heat transfer and consequently to excessively rapid deflation profiles for associated inflatable restraint devices. To mitigate the effects of high temperature materials, it is common to relegate a significant portion of the mass of an inflator assembly to at least in part to function or serve as a heat sink. Unfortunately, such practice can undesirably impact both the efficiency of the system and the weight of the inflator.
In addition to the above, there is an ongoing challenge to simplify or facilitate manufacture and assembly as well as to reduce the associated costs in the design and development of modern vehicles and the assemblies and components included therewithin, such as inflator assemblies included in vehicle occupant safety restraint systems.